I have always changed coaches because the coaches have usually moved on from coaching or moved to another rink. Have never had to leave a coach because things were unpleasant or didn't get on with them. In fact one coach (ice dance) I've had for 16 years, just because I really enjoy learning from her and am still learning. I am lucky because I also consider her a good friend after all this time.
But interested to know why people have left coaches. Were they were teaching you wrong technique? You felt like you were getting ripped off? You just couldn't get on with them? Or they could only teach to a certain level and to develop you had to move on? Or did the coach drop you as a student?
Thought this would make a good discussion.